The present invention relates to a method of producing a toroidal carcass for a road vehicle tire.
More specifically the present invention relates to a straightforward, low-cost method of producing a toroidal carcass for radial tires; the carcass being a woven carcass of the type in which two annular beads are connected by a reticulated structure comprising a number of elongated reinforcing elements, which are wound about the beads to connect the beads to each other, and which extend in substantially radial planes with respect to the beads.
A carcass of the above type is known to be produced using a forming device comprising a removable annular element, which is located radially outwards of the two beads, and is centered axially with respect to the beads to define, with the beads, a toroidal frame having two annular openings, each located between the annular element and a respective bead. The known forming device also comprises a frame supporting and activating unit for rotating the frame about its axis; and a winding device, which, as the frame rotates, winds a cord about the frame along a spiral path, each turn of which comprises a first half-turn entirely outside the frame, and a second half-turn extending through the two openings in the frame and connected to the other half-turn outside the two beads.
The cord is normally wound along said spiral path about the frame by means of a device for feeding along the spiral path a cartridge carrying a supply of cord. Completion of the carcass using such cartridges obviously poses serious difficulties in that, as the distance between the start and end of the spiral path gets smaller, the opening between the start and end of the path eventually becomes too small to allow passage of the cartridge, which must therefore be replaced with increasingly narrower cartridges to complete the woven carcass.
In addition to the downtime involved, such cartridge changes also result in the formation of dangerous knots in the cord.